Well, the link to the previous game jam is easy to find, just replace the 2 with 1 like this:
https://itch.io/jam/rpg-maker-horror-game-jam-1
There were actually 20 more game jams before that one which had a different naming pattern, I reset the count for various reason, but just like with the previous example, simly change the numbering part of the url and it should bring you to where you need:
https://itch.io/jam/20th-rpg-maker-horror-game-jam
https://itch.io/jam/19th-rpg-maker-horror-game-jam
https://itch.io/jam/18th-rpg-maker-horror-game-jam
https://itch.io/jam/17th-rpg-maker-horror-game-jam
etc.
I also have a collection on my profile page where the majority of the entries to the past game jams is: